/* Copyright (C) 2004 - 2006  db4objects Inc.  http://www.db4o.com

This file is part of the db4o open source object database.

db4o is free software; you can redistribute it and/or modify it under
the terms of version 2 of the GNU General Public License as published
by the Free Software Foundation and as clarified by db4objects' GPL 
interpretation policy, available at
http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
Suite 350, San Mateo, CA 94403, USA.

db4o is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. */
namespace Mono.Cecil.Cil {

	using System;
	using System.Collections;
	using SR = System.Reflection;

	using Mono.Cecil;

	public sealed class CilWorker : ICilWorker {

		MethodBody m_mbody;
		InstructionCollection m_instrs;

		internal CilWorker (MethodBody body)
		{
			m_mbody = body;
			m_instrs = m_mbody.Instructions as InstructionCollection;
		}

		public MethodBody GetBody ()
		{
			return m_mbody;
		}

		public Instruction Create (OpCode opcode)
		{
			if (opcode.OperandType != OperandType.InlineNone)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode);
		}

		public Instruction Create (OpCode opcode, TypeReference type)
		{
			if (opcode.OperandType != OperandType.InlineType &&
				opcode.OperandType != OperandType.InlineTok)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, type);
		}

		public Instruction Create (OpCode opcode, MethodReference meth)
		{
			if (opcode.OperandType != OperandType.InlineMethod &&
				opcode.OperandType != OperandType.InlineTok)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, meth);
		}

		public Instruction Create (OpCode opcode, FieldReference field)
		{
			if (opcode.OperandType != OperandType.InlineField &&
				opcode.OperandType != OperandType.InlineTok)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, field);
		}

		public Instruction Create (OpCode opcode, string str)
		{
			if (opcode.OperandType != OperandType.InlineString)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, str);
		}

		public Instruction Create (OpCode opcode, sbyte b)
		{
			if (opcode.OperandType != OperandType.ShortInlineI &&
				opcode != OpCodes.Ldc_I4_S)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, b);
		}

		public Instruction Create (OpCode opcode, byte b)
		{
			if (opcode.OperandType != OperandType.ShortInlineI ||
				opcode == OpCodes.Ldc_I4_S)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, b);
		}

		public Instruction Create (OpCode opcode, int i)
		{
			if (opcode.OperandType != OperandType.InlineI)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, i);
		}

		public Instruction Create (OpCode opcode, long l)
		{
			if (opcode.OperandType != OperandType.InlineI8)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, l);
		}

		public Instruction Create (OpCode opcode, float f)
		{
			if (opcode.OperandType != OperandType.ShortInlineR)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, f);
		}

		public Instruction Create (OpCode opcode, double d)
		{
			if (opcode.OperandType != OperandType.InlineR)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, d);
		}

		public Instruction Create (OpCode opcode, Instruction label)
		{
			if (opcode.OperandType != OperandType.InlineBrTarget &&
				opcode.OperandType != OperandType.ShortInlineBrTarget)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, label);
		}

		public Instruction Create (OpCode opcode, Instruction [] labels)
		{
			if (opcode.OperandType != OperandType.InlineSwitch)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, labels);
		}

		public Instruction Create (OpCode opcode, VariableDefinition var)
		{
			if (opcode.OperandType != OperandType.ShortInlineVar &&
				opcode.OperandType != OperandType.InlineVar)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, var);
		}

		public Instruction Create (OpCode opcode, ParameterDefinition param)
		{
			if (opcode.OperandType != OperandType.ShortInlineParam &&
				opcode.OperandType != OperandType.InlineParam)
				throw new ArgumentException ("opcode");

			return FinalCreate (opcode, param);
		}

		Instruction FinalCreate (OpCode opcode)
		{
			return FinalCreate (opcode, null);
		}

		Instruction FinalCreate (OpCode opcode, object operand)
		{
			return new Instruction (opcode, operand);
		}

		public Instruction Emit (OpCode opcode)
		{
			Instruction instr = Create (opcode);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, TypeReference type)
		{
			Instruction instr = Create (opcode, type);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, MethodReference meth)
		{
			Instruction instr = Create (opcode, meth);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, FieldReference field)
		{
			Instruction instr = Create (opcode, field);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, string str)
		{
			Instruction instr = Create (opcode, str);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, byte b)
		{
			Instruction instr = Create (opcode, b);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, sbyte b)
		{
			Instruction instr = Create (opcode, b);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, int i)
		{
			Instruction instr = Create (opcode, i);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, long l)
		{
			Instruction instr = Create (opcode, l);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, float f)
		{
			Instruction instr = Create (opcode, f);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, double d)
		{
			Instruction instr = Create (opcode, d);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, Instruction target)
		{
			Instruction instr = Create (opcode, target);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, Instruction [] targets)
		{
			Instruction instr = Create (opcode, targets);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, VariableDefinition var)
		{
			Instruction instr = Create (opcode, var);
			Append (instr);
			return instr;
		}

		public Instruction Emit (OpCode opcode, ParameterDefinition param)
		{
			Instruction instr = Create (opcode, param);
			Append (instr);
			return instr;
		}

		public void InsertBefore (Instruction target, Instruction instr)
		{
			int index = m_instrs.IndexOf (target);
			if (index == -1)
				throw new ReflectionException ("Target instruction not in method body");

			m_instrs.Insert (index, instr);
			instr.Previous = target.Previous;
			target.Previous = instr;
			instr.Next = target;
		}

		public void InsertAfter (Instruction target, Instruction instr)
		{
			int index = m_instrs.IndexOf (target);
			if (index == -1)
				throw new ReflectionException ("Target instruction not in method body");

			m_instrs.Insert (index + 1, instr);
			instr.Next = target.Next;
			target.Next = instr;
			instr.Previous = target;
		}

		public void Append (Instruction instr)
		{
			Instruction last = null, current = instr;
			if (m_instrs.Count > 0)
				last = m_instrs [m_instrs.Count - 1];

			if (last != null) {
				last.Next = instr;
				current.Previous = last;
			}

			m_instrs.Add (current);
		}

		public void Replace (Instruction old, Instruction instr)
		{
			int index = m_instrs.IndexOf (old);
			if (index == -1)
				throw new ReflectionException ("Target instruction not in method body");

			InsertAfter (old, instr);
			Remove (old);
		}

		public void Remove (Instruction instr)
		{
			if (!m_instrs.Contains (instr))
				throw new ReflectionException ("Instruction not in method body");

			if (instr.Previous != null)
				instr.Previous.Next = instr.Next;
			if (instr.Next != null)
				instr.Next.Previous = instr.Previous;
			m_instrs.Remove (instr);
		}
	}
}